1. Field of the Invention
The present invention relates to a wireless localization method and a wireless localization apparatus, which use a fingerprinting technique, and more particularly, to a wireless localization method and a wireless localization apparatus, which use a fingerprinting technique, wherein a location of a predetermined node is estimated by using a received signal strength (RSS)-based fingerprinting wireless localization technique, and a frequency is assigned according to regions by using the estimated location.
2. Description of the Related Art
Wireless localization technologies and various applications for providing a location-based service (LBS) are being developed according to a rapid increase of smart phone users and innovative development of mobile communication technologies. Examples of such a technology for providing location information include a global positioning system (GPS) using a satellite network, and a mobile communication network based wide area wireless localization technology. Recently, studies on wireless localization techniques using a wireless local area network (WLAN), ZigBee, or Bluetooth indoor and outdoor are being actively performed.
Specifically, it is important to provide location information in real-time by using wireless localization, even in a machine-to-machine (M2M) communication providing various types of information about a person and an object as a machine and an information technology (IT) are combined together. Factories are gradually turning to intelligent autonomous production. Managers of such factories are aiming at recognizing and managing operation states, locations, and environments of machines in the factories by using the M2M communication and the wireless localization technology. However, WLAN, Bluetooth, and ZigBee usable in M2M factories share industrial scientific medical (ISM) bands, and thus frequency interference may be generated between machines. Moreover, performance may be deteriorated, such as quality deterioration and delay, due to communication inability or communication error caused by the frequency interference.
Techniques for efficiently managing signal frequency interference generated in the M2M communication as such need to be studied. Examples of a conventional method of managing frequency interference include a cognitive radio method, a power control method, and a beamforming method.
First, according to the cognitive radio method, if a primary user assigned with a certain frequency does not use the certain frequency, a secondary user may use the certain frequency without interfering with the primary user. Accordingly, an empty frequency band may be suitably used to prevent frequency resource scarcity, and since a frequency resource limited by a situation cognitive ability may be reused according to time, space, and region, frequencies may be efficiently managed while avoiding interference. Also, since the cognitive radio method may actively react to given environments, a best quality of service in the given environment may be guaranteed to a user using a cognitive radio system, and thus the cognitive radio method is getting the limelight in recent next-generation wireless communication fields. However, complexity of the cognitive radio method may be remarkably increased when all frequency bands are detected without omission for frequency interference management and an empty frequency band is used.
The power control method is a simplest method for suppressing frequency interference, wherein transmission power is adjusted such that a signal is transmitted at minimum transmission power that satisfies required communication quality. The power control method is currently used in most wireless communication systems, specifically to prevent interference between cells in a mobile communication system.
The beamforming method uses a smart antenna, wherein a beam of an antenna is steered only to a corresponding terminal. Here, a radiation pattern of the smart antenna is prepared by forming beams in a direction of a mobile terminal or a target and removing a beam pattern of the target or the mobile terminal that is not desired or is in the way. However, such conventional methods have low economic efficiency since they are widely used in cellular network environments, have massive throughputs, and need a separate apparatus aside from an M2M apparatus used in indoor factories.
Thus, frequency interference may be efficiently managed by improving wireless localization performance when a fingerprinting technique that is recently getting the spotlight as an indoor wireless localization technology is applied to the frequency managing technique. A background technology of the present invention is disclosed in KR2011-0116565.